1. Field of the Invention
The present invention relates to a side view Light Emitting Diode (LED) including a protective device. More particularly, the present invention relates to a side view LED which has a partition wall formed between an LED chip and a protective device to prevent light absorption by the protective device, and is designed to improve electrical connections between the devices and lead frames.
2. Description of the Related Art
A small Liquid Crystal Device (LCD) used in mobile phones, Personal Digital Assistants (PDAs) and the like employs a side view Light Emitting Diode (LED) as a light source for its back light device. Such a side view LED is typically mounted in the backlight device as shown in FIG. 1.
Referring to FIG. 1, the backlight device 50 has a flat light guide plate 54 formed on a substrate 52. Also, a plurality of side-view LEDs 1 (only one LED illustrated) are arrayed on a side of the light guide pate 54. Light L incident into the light guide plate 54 from the LEDs is reflected upward by a reflective sheet 56 or microdot patterns formed on the light guide plate 54. Then the light L exits from the light guide plate 54 to provide a backlight to an LCD panel 58 over the light guide panel 54.
The LED is purportedly susceptible to static electricity, inverse voltage or over voltage. Especially, the side view LED needs to be extremely thin and accordingly an LED chip mounted is downscaled. This renders the LED greatly affected by undesired effects of current/voltage so that it is imperative to prevent them.
To this end, a voltage regulation diode is provided to the LED. That is, the voltage regulation diode is connected to the LED chip in parallel to effectively counter static electricity. Preferably, the voltage regulation diode is exemplified by a Zener diode.
Then, a detailed explanation will be given about a conventional side view LED having a Zener diode mounted therein with reference to FIGS. 2 and 3.
FIG. 2 is a front elevation view illustrating the side view LED having the Zener diode mounted therein according to the prior art. FIG. 3 is a cross-sectional view cut along the line 3-3 of FIG. 2.
As shown in FIGS. 2 and 3, the conventional LED 1 includes a package body 10, a pair of leads 20 and 22 spaced apart from each other at a predetermined gap and an LED chip 30 mounted on the lead 20.
The LED chip 30 is connected to the leads 20 and 22 via wires 32 and encapsulated by a transparent encapsulant 14 provided into a cup-shaped concave 12 therearound.
Meanwhile, a Zener diode 40 is mounted on the lead 22 and connected thereto via a wire 34. In this fashion, the Zener diode 40 is connected to the LED chip 30 in parallel, thereby protecting the LED chip 30 from static electricity, inverse voltage or over voltage.
The Zener diode 40, which belongs to a semiconductor PN junction diode, is structured such that it operates in a breakdown area of the PN junction. Thus the Zener diode 40 is chiefly used for voltage regulation or to ensure a constant voltage. The Zener diode 40 obtains a predetermined voltage via a zener recovery phenomenon. Also, the Zener diode 40 operates at a current of 10 mA when having a p-n junction of silicon and may produce a constant voltage of 3 to 12V depending on its type.
However, in the conventional LED 1, the Zener diode 40 is coplanarly disposed with the LED chip 30 in parallel so that light generated from the LED chip is absorbed or scattered by the Zener diode 40, thereby degrading light emitting efficiency of the LED 1.
Also, with the LED chip 30 and Zener diode 40 disposed in the narrow concave 12, the wires 32 and 34 should be disposed at a predetermined gap so that they do not contact one another. This requires a meticulous and deliberate process and accordingly undermines efficiency in fabricating the LED.